Lagrangian model using CFD flow data to predict the currentvoltage characteristics of a solid oxide fuel cell repeat unit

A model framework is presented to predict the current-voltage (I-U) characteristics and hence the electrical performance of a solid oxide fuel cell (SOFC) repeat unit, i.e., a planar SOFC with adjacent current collector plates. The model uses as input residence times obtained from 3D CFD data for the fuel flowing through the anodic gas channels of a current collector plate. These residence times are then used by an electrochemical model to predict the fuel conversion along different flow paths for various electrical loads. This way, the overall (I-U) behaviour of the repeat unit follows from combining the fuel conversion rates (and respective electrical currents) for the individual flow paths. Since we use a Lagrangian reference frame for the electrochemical model, for a given electrical load, only a simple time-integration of a first-order ODE is required. Therefore, this modelling approach is very efficient and well suited for extensive parameter studies, e.g., to optimise the fuel residence times with respect to the electrical performance of the repeat unit. To ensure its reliability, the model has been validated by comparison with both experimental data and other (I-U) models.